Health Videos

Phentermine tablets or capsules

What is this medicine?

PHENTERMINE (FEN ter meen) decreases your appetite. It is used with a reduced calorie diet and exercise to help you lose weight.

How should I use this medicine?

Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. The instructions for use may differ based on the product and dose you are taking. Avoid taking this medicine in the evening. It may interfere with sleep. Take your doses at regular intervals. Do not take your medicine more often than directed.

Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for children 17 years or older for selected conditions, precautions do apply.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:

allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue)

anxiety

breathing problems

changes in vision

chest pain or chest tightness

depressed mood or other mood changes

hallucinations, loss of contact with reality

fast, irregular heartbeat

increased blood pressure

irritable

nervousness or restlessness

painful urination

palpitations

tremors

trouble sleeping

seizures

signs and symptoms of a stroke like changes in vision; confusion; trouble speaking or understanding; severe headaches; sudden numbness or weakness of the face, arm or leg; trouble walking; dizziness; loss of balance or coordination

unusually weak or tired

vomiting

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

constipation or diarrhea

dry mouth

headache

nausea

stomach upset

sweating

What may interact with this medicine?

Do not take this medicine with any of the following medications:

MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate

medicines for colds or breathing difficulties like pseudoephedrine or phenylephrine

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

Where should I keep my medicine?

Keep out of the reach of children. This medicine can be abused. Keep your medicine in a safe place to protect it from theft. Do not share this medicine with anyone. Selling or giving away this medicine is dangerous and against the law.

This medicine may cause accidental overdose and death if taken by other adults, children, or pets. Mix any unused medicine with a substance like cat litter or coffee grounds. Then throw the medicine away in a sealed container like a sealed bag or a coffee can with a lid. Do not use the medicine after the expiration date.

an unusual or allergic reaction to phentermine, other medicines, foods, dyes, or preservatives

pregnant or trying to get pregnant

breast-feeding

What should I watch for while using this medicine?

Notify your physician immediately if you become short of breath while doing your normal activities.

Do not take this medicine within 6 hours of bedtime. It can keep you from getting to sleep. Avoid drinks that contain caffeine and try to stick to a regular bedtime every night.

This medicine was intended to be used in addition to a healthy diet and exercise. The best results are achieved this way. This medicine is only indicated for short-term use. Eventually your weight loss may level out. At that point, the drug will only help you maintain your new weight. Do not increase or in any way change your dose without consulting your doctor.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may increase dizziness and drowsiness. Avoid alcoholic drinks.